Influence of nanoclay content on polypropylene properties and recycling of nanocomposites obtained by injection

ABSTRACT In this work, polypropylene and organophilic montmorillonite PP/MMTO nanocomposites were prepared at the concentrations of 1, 2, 5 and 7 % were prepared through the melt intercalation by directly at the single screw hydraulic injector. The obtained material was processed, obtaining specimens called ties in the form of ties. Reprocessing was performed by milling the material in a knife mill. Soon after the ground material was injected again obtaining the second cycle of the material and, later, until reaching the fourth cycle. The samples were evaluated by scanning electron microscopy (SEM), mechanical tensile test, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results of tensile strength and Young's modulus for the nanoclay containing formulations did not show significant changes, causing the nanoclay to act only as a charge. The TGA analysis showed that when 2% MMTO was added, the degradation temperature (Tonset) increased 17.10% when compared to PP, which was the best result found. The DSC curves did not show variation in the melt temperature (Tm2) for the formulations containing MMTO and also for the reprocessed formulations. On the other hand, the degree of crystallization (αc) showed significant variations, with emphasis on the formulation with 5% MMTO, where αc was 66.70%, about 26.80% higher than PP.